New Insights on HbA1c Testing for Diabetes in India
A recent study featured in ‘The Lancet Regional Health’ raises questions about the accuracy of glycated hemoglobin (HbA1c) testing, a common method used in India for identifying type-2 diabetes. The study suggests that this test might not truly reflect an individual’s blood glucose levels, potentially skewing the real picture of diabetes prevalence in the country.
The findings indicate that the issues may be more pronounced in areas where anemia, hemoglobinopathies, and red blood cell enzyme deficiencies, like G6PD deficiency, are widespread. Professor Anoop Misra, a key author of the study and chairman at Fortis C-DOC Centre of Excellence for Diabetes, pointed out that relying solely on HbA1c could lead to misclassifying diabetes. This misclassification might result in some people receiving their diagnoses later than necessary, while others could be misdiagnosed entirely—compromising effective treatment and monitoring of blood sugar levels.
The review is based on extensive data that challenges the dependence on HbA1c as the only diagnostic or monitoring method for type-2 diabetes in South Asia. Essentially, HbA1c measures the glycation of hemoglobin, but conditions that affect hemoglobin—like anemia or certain inherited disorders—can significantly alter HbA1c results, thus providing misleading approximations of average blood glucose.
Co-author Shashank Joshi from Joshi Clinic in Mumbai added that even in well-equipped urban hospitals, HbA1c values can fluctuate due to variations in red blood cells and genetic factors. In rural or tribal settings, where anemia is more common, the potential for discrepancies in HbA1c readings is even greater.
According to the study, over 50% of the population in some parts of India are nutritionally challenged, notably with prevalent iron deficiency anemia, which complicates HbA1c readings. This miscalculation can hinder both diagnosis and monitoring, with the possibility of delaying the correct diagnosis by as much as four years for men who are unaware of having G6PD deficiency, thereby heightening their risk of complications.
Inconsistent quality control among laboratories further complicates the accuracy of HbA1c testing, making accurate diagnoses even more challenging. The study cautions that public health surveys that rely solely on HbA1c might not accurately represent the diabetes situation in India.
In response to these findings, the authors propose a framework suited for India’s diverse healthcare landscape. In areas with fewer resources, they suggest using the oral glucose tolerance test (OGTT)—which involves measuring glucose levels before and two hours after consuming glucose—as the primary diagnostic method. For self-monitoring, the report recommends regular blood glucose checks combined with basic hematological assessments.
In tertiary care facilities, the study advises pairing HbA1c tests, performed with standardized equipment, with OGTT for diagnosis. For ongoing monitoring, it recommends continuous glucose monitoring methods combined with alternative markers, such as fructosamine.
